Local Area Network (LAN)
Local Area Network (LAN)
Networks used to interconnect computers in a single room, rooms within a building or buildings on one site are called Local Area Network (LAN).
LAN links computers, i.e., software and hardware, in the same area for the purpose of sharing information. Usually LAN links computers within a limited geographical area because they must be connected by a cable, which is quite expensive.
Characteristics of LAN :
- Every computer has the potential to communicate with any other computers of the network
- High degree of interconnection between computers
- Easy physical connection of computers in a network
- Inexpensive medium of data transmission
- High data transmission rate
Advantages of LAN
- The reliability of network is high because the failure of one computer in the network does not effect the functioning for other computers.
- Addition of new computer to network is easy.
- High rate of data transmission is possible.
- Peripheral devices like magnetic disk and printer can be shared by other computers.
Disadvantages of LAN
- If the communication line fails, the entire network system breaks down.
Use of LAN
- File transfers and Access
- Word and text processing
- Electronic message handling
- Remote database access
- Personal computing
- Digital voice transmission and storage
- The Internet is a net consisting of complex network of computers connected by high speed communication technologies.
- The Internet has penetrated and benefited every field – be it education, sports, news, business, etc.
- A web page can be designed using HTML.
- The Internet has converted the world into a global village.
- The Internet has led to faster globalisation. A web page is an electronic document that we can see on the Internet.
- Web browser is software required to view web pages.
- Mosaic was the first web browser.
- www is stand for World Wide Web.
- Electronic mail can be sent and received through any e-mail account.
- Downloading is saving of files from the Internet to our computer.
- Attachments are the extra files that we can send with our email.
- E-commerce stands for electronic-commerce which means buying and selling over the Internet.
- M-commerce is an emerging field which stands for mobile commerce.
- Teleconferencing is having online conference with the facility of exchanging thoughts using an audio.
- Videoconferencing means having online conference with the facility of seeing and listening to other participants.
- Telecommunication is the use of electronic system to send and receive voice, data and video messages.
- Broadly there are five components of communication system, namely information/ message, device, application, protocol and network.
- Voice communication requires telephone instruments like telephone, mobile or VoIP phones for PSTN, wireless or data network.
- Data communication allows transfer of information and remote management of devices.
- Data communication is undertaken by directly connected computers, printers, etc. in a Local Area Network.
- Long distance data communication is done through point to point connections using PSTN or wireless networks.
- Broadcasting of audio and telecasting of video service such as radio and television is done through wireless links.
- Ethernet is the most popular LAN technology for data communication which provides communication speed up to 10Gbps.
- Internet Protocol (IP) connects the computer across similar or diverse networks.
- In IP, data packets are transmitted in packets containing unique IP addresses for the source and the destination.
- IP automatically routes the packet to its destination through any available path.
- Convergence of technologies is required to meet the next generation unified applications where all the three forms of data are required to be transmitted simultaneously.
- IP is internationally accepted protocol through which all different forms of data can be communicated.
- The approach to convergence is to make all components of communication systems IP enabled.
- While trying to achieve convergence, effort is on to use existing infrastructure with partial upgradation.
- Broadband and IPTV are two next generation technologies which use PSTN to provide unified services for voice, data and video.
- VoIP is a data communication technology which allows IP phones and computers to connect to telephones through PSTN and mobile networks.
- Unified messaging system is provided by web service providers which can be used to access multiple services like e-mail, chat, call and entertainment from a single computer system with Internet connection.
- Standardisation is very important for interoperability of various components in any system,
- There are organisations which develop standards, rules and specification for a product that the manufacturers have to meet.